Medicaid is a key source of insurance coverage and health care for individuals with co- occurring mental and physical health conditions. Yet the complexity of health service needs for these individuals, often delivered through a fragmented system, contributes to expensive and low quality health care. In response, managed care delivery models have become a popular mechanism to increase mental and physical care integration and coordination while restraining or ensuring greater predictability of costs. However, little is known about managed care's effects on quality and costs of care for this vulnerable subpopulation with mental and medical health comorbidity. There is concern that savings may be achieved by reducing quality or access to care rather than through encouraging more appropriate care utilization; a result which would further jeopardize the well-being of an already vulnerable group. Thus, the objective of this Kirschstein-NRSA individual fellowship (F30) proposal is to assess the effects of comprehensive managed care on the quality and costs of health care for adults in Medicaid Managed Care (MMC) with co-occurring physical and mental illness relative to fee-for-service (FFS) or primary-care case management (PCCM) health service delivery. This goal will be achieved by leveraging a natural experiment in Texas where mandatory MMC enrollment was legislated in 2007 and 2011 for a subset of Texas' 254 counties. The proposed studies will utilize quasi-experimental designs with methodologically strong, controlled time-trend analyses to provide ecologically valid information with immediate relevance to policy decision-makers. This work will seek to achieve three specific aims: (1) characterize the effect of the 2007 and 2011 Texas MMC expansions on nationally-validated quality of chronic, behavioral and preventative care measures compared to FFS or PCCM; (2) examine trends in total health care expenditures as well as inpatient, outpatient and emergency department utilization for enrollees in the 2007 and 2011 Texas MMC expansions relative to FFS or PCCM; and (3) integrate these findings on quality and cost, and develop and implement a plan for dissemination to policy-makers, agency and program leaders. As a concurrent benefit, this fellowship will provide the applicant with carefully constructed training which integrates clinical medicine, longitudinal and multi-level modeling, health economics, and implementation science. The coursework, mentored research and manuscript writing with his Co-Sponsors, and planned interaction at professional meetings will further this applicant's career goal as an independent clinician-scientist seeking to understand and correct health inequities for vulnerable populations through health service delivery improvements. Thus, this research directly targets NIMH's Strategies 3.4 and 4.1 by examining the comparative effectiveness of state-policy mandated systems-level delivery interventions using existing, longer- term follow-up data, broader, stakeholder-relevant outcomes, and innovative quasi-experimental study design that yields strong levels of inference to understand the gap between optimal and typical care.